LED bulbs failures

[friendly_jacek]

Quote:
Five types of bulb, some costing more than £10, stopped working before 6,000 hours in the majority of samples tested.

Another five failed before 10,000 hours for the majority of samples tested, despite claiming lifespans of at least 25,000 hours. In total, 66 of the 230 samples failed before 10,000 hours, though all claimed to last at least 15,000.


http://www.dailymail.co.uk/news/article-...kers-claim.html

I got lots cheap LEDs on ebay at an average price of $1. The early mortality rate is about 10%.

 

[Quest]

we are still into the early stages of LED lightbulb adoption, so high manufacturing costs, compounded with Chinese made garbage using us as the usual dumping ground, typically ended up with high failure rates and disgruntled consumers.

This is more or less the same thing that happened during early stages of chinese made cheep spiral CFL lightbulbs in the market a few moons ago....

BTW: just like a cheep pair of sneakers: you get what you paid for RE: LED bulbs.

Q.

 

[jrustles]

yeah, true that.

Those MTBF ratings are largely theoretical!!

The Chinese have a bad habit of overdriving their LEDs because why not get more initial output from less chips? Combined with horrible thermal management and the aforementioned cheapest components possible, and I'm surprised they last as long as they do THB lol

 

[JHZR2]

Remember that there isn't necessarily a ton of difference in the circuit and its cost point between low-life CFLs and the LEDs that are out there. And LEDs DO run HOT, if you touch their heatsinks.

So there still is some engineering behind this stuff and it isn't necessarily cut and dry.

Still I like LEDs and use them where it makes sense. Some fixtures Ive liked CFLs better in, actually, so there they remain.

 

[Donald]

I like LEDs where dimming is needed like fan light bulbs. For my garage and workshop I use 120 equiv watt bright white CFLs. They are amazing in how much bright light they provide.

 

[sciphi]

Skip the Chinese-made ones and purchase US-made (at least assembled) LED bulbs. The Cree LED bulbs at HD (and quite a few of the HD house-brand bulbs) are assembled in the States. So at least a fellow American got a job out of the deal. And, they seem to provide a better light than the Chinese LED bulbs I've used.

 

[Rand]

I like the CFL's with the 2-1 adapters in my basement... no longer a peehole in a snowdrift down there.

it is bright to look at the bare bulbs but hey its the unfinished basement.

 

[Quest]

Most cheeply made/executed LED bulbs typically suffers from shortened service life mainly due to 1 of the 2 issues:

(1) overdriven P-N junction on the LED itself, which, drastically reduced the service life of them (well known issues since the dawn of LED in the 60s).

(2) insufficient cooling. Have you every noticed that unlike CFL, LED bulbs would require a huge chunk of aluminium as heat sink? This primarily has to do with the need from keeping the P-N junction (where light emissions come from) from thermal run-away...and to a somewhat lesser extent: the internal circuitry's IC or solid state component cooling (aka "heat sink").

When any of these 2 are not done right, it's a recipe for premature bulb failure, simple as that.

so far, my luck has been favouring FEIT, Philips, Cree (HD), Ikea (40Watt varieties), and some GeeEee 40Watt equiv. bulbs...some do run hot but most of them seems to be ok.

as far as colour rendition's concerned: Cree, Philips, Ikea, get my vote for being close (in terms of colour) to what they said they would, unlike some cheeply made ones that the colour can be all over the place (overly blue, or with blue hue, green, yellow-green colour, etc.)

Q.

 

[friendly_jacek]

This confirmed what I was thinking: power supply failures due to cheap components:

Quote:
Engineers looking into the premature failure of LED lamps in commercial lighting, such as traffic signals and street lighting have discovered the root cause for the majority of the failures of these lights are not the LED’s themselves failing, but the power supplies required to convert and regulate the 120 volt line power to the voltage levels required by the LED strings. It turns out while the LED lamps have a Energy Star design life of over 25,000 for residential applications and 35,000 hours in commercial applications and the LED themselves have a possible lifespan of over 45,000 hours, these numbers become irrelevant when the power supplies routinely fail in less than 20,000 hours.

It seems the weak links in the chain are the electrolytic capacitors in he power supplies which where never designed for a long life span, a lifespan that is severely shortened by the high temperature the power supplies work under.

Two solutions detailed in the article are a compete redesign of the power supply to one that is less efficient and will be more expensive in the beginning, but does not utilize electrolytic capacitors and or powering the LED fixtures from a DC circuit which requires either utilizing an additional power supply to convert the 120 volts AC to 48 volts DC upfront (furthering lowering overall efficiency and increasing installed costs) or re-wring the infrastructure to where home and commercial structures would be dual voltage 120/240 AC and 48 volts DC.

Personally I believe the short term solution will be a redesign of the LED power supplies resulting in a spike in LED lamp prices and long term as solar becomes more prevalent homes and commercial building will be dual voltage AC/DC wired.

None the less this “problem” is becoming a serious thorn in the sides of the manufacturers and supporters of LED’s for lighting.

The full article can be found here.

»www.edn.com/blog/PowerSource/416···20120223


http://www.dslreports.com/forum/r26935697-LED-Lighting-Born-To-Fail.
Sadly, the link to the study is dead.

 

[CBR.worm]

I haven't had an LED bulb fail yet, and my house is lit almost exclusively by LED's, but they are all old Phillips or Cree based. I never had CFLs last this long.

Most of my bulbs are 3-5 years old. I don't know what that works out to be hour wise. Only the light over the stairs runs 24x7

 

[Blaze]

I got bit by the flickering Chinese LED's. Two of them made by GE.

 

[Pop_Rivit]

I've had no issues whatsoever with any of the LED bulbs that I've been using for the last 3 months. I replaced nearly all of the incandescent bulbs with (about 90) LED bulbs-mostly Cree and Utilitech along with some GU10 replacements.

So far I've been quite pleased with their performance, and I'm seeing about $1/day electric savings-although I expect that to go down as our lighting needs are reduced for the summer months.

 

[zzyzzx]

I think they should make LED bulbs shaped like a CFL, so it will dissipate heat better.

 

[friendly_jacek]

Found a reason why cheap LEDs fail a lot: lack of thermal paste.

Quote:
The problem of blowing LEDs IMHO is mainly caused in these Chinese lamps by the total lack or insufficient quantity of thermal heatsink paste at the point where the mounting disc meats the heatsink flange. LEDs generate a lot of heat and the heat must be carried away efficiently and quickly or the LEDs will be damaged or fail completely.
Two months ago I ordered another bunch of LED lamps. This time, before used them I checked each lamp for thermal integrity. In 8 lamps, I found two with NO THERMAL PASTE - at all. I found two more with patently insufficient amount of thermal paste.

I put plenty of CPU type thermal paste on the heatsink flanges of these lamps and they have been burning for 15+ hours a day since - and none have failed or blown in this batch.- I hope I have cracked it!!

The cost is only a few cents per lamp and about five minutes of my time. I now hope that I have good quality LED lamps.


I went ahead and ordered a tube of 25g of thermal paste.

 

[Quest]

Originally Posted By: friendly_jacek
Found a reason why cheap LEDs fail a lot: lack of thermal paste.

Quote:
The problem of blowing LEDs IMHO is mainly caused in these Chinese lamps by the total lack or insufficient quantity of thermal heatsink paste at the point where the mounting disc meats the heatsink flange. LEDs generate a lot of heat and the heat must be carried away efficiently and quickly or the LEDs will be damaged or fail completely.
Two months ago I ordered another bunch of LED lamps. This time, before used them I checked each lamp for thermal integrity. In 8 lamps, I found two with NO THERMAL PASTE - at all. I found two more with patently insufficient amount of thermal paste.

I put plenty of CPU type thermal paste on the heatsink flanges of these lamps and they have been burning for 15+ hours a day since - and none have failed or blown in this batch.- I hope I have cracked it!!

The cost is only a few cents per lamp and about five minutes of my time. I now hope that I have good quality LED lamps.


I went ahead and ordered a tube of 25g of thermal paste.


LOL! inappropriate means of applying thermal paste will not help resolve otherwise poorly executed (constructed) LED issues.

Q.

 

[JHZR2]

Originally Posted By: Pop_Rivit
I've had no issues whatsoever with any of the LED bulbs that I've been using for the last 3 months. I replaced nearly all of the incandescent bulbs with (about 90) LED bulbs-mostly Cree and Utilitech along with some GU10 replacements.

So far I've been quite pleased with their performance, and I'm seeing about $1/day electric savings-although I expect that to go down as our lighting needs are reduced for the summer months.



You've got a nice set to have good statistics, but you're only currently qualified to state infant mortality. What will be interesting is after a year or three.

Other than CFLs that blew in less than 10 hours, even the worst lasted over a year IME. Now some have been in service in my home for 7+ years while others have blew in a few.